ESB-2017.1786 - [Appliance] Rockwell Automation MicroLogix 1100 Controllers: Denial of service - Remote/unauthenticated 2017-07-21

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             AUSCERT External Security Bulletin Redistribution

 Advisory (ICSA-17-138-03) Rockwell Automation MicroLogix 1100 Controllers
                               21 July 2017


        AusCERT Security Bulletin Summary

Product:           Rockwell Automation MicroLogix 1100 Controllers
Publisher:         ICS-CERT
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2017-7924  

Original Bulletin:

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Advisory (ICSA-17-138-03)

Rockwell Automation MicroLogix 1100 Controllers

Original release date: July 18, 2017

Legal Notice

All information products included in are provided
"as is" for informational purposes only. The Department of Homeland Security 
(DHS) does not provide any warranties of any kind regarding any information 
contained within. DHS does not endorse any commercial product or service, 
referenced in this product or otherwise. Further dissemination of this product
is governed by the Traffic Light Protocol (TLP) marking in the header. For 
more information about TLP, see

CVSS v3 7.5

Vendor: Rockwell Automation

Equipment: MicroLogix 1100 Controllers

Vulnerability: Improper Input Validation


This advisory was originally posted to the NCCIC Portal on May 18, 2017, and 
is being released to the NCCIC/ICS-CERT web site.


The following versions of MicroLogix 1100 controllers are affected:



1763-L16BBB, and



Successful exploitation of this vulnerability could cause the device that the
attacker is accessing to enter a Denial-of-Service (DoS) condition.


Rockwell Automation recommends updating to the latest firmware revision of 
MicroLogix 1100 controllers, Version FRN 16.0 or later, which is available at
the following location:
(link is external)

For more information on this vulnerability and more detailed mitigation 
instructions, please see Rockwell Automation's advisory at the following 
location: (link
is external)

As well as Rockwell Automation's security page: (link is external)

ICS-CERT and Rockwell Automation recommend that users take defensive measures
to minimize the risk of exploitation of this vulnerability. Specifically, 
users should:

Block all traffic to EtherNet/IP or other CIP protocol-based devices from 
outside the Manufacturing Zone by blocking or restricting access to Port 
2222/TCP and UDP and Port 44818/TCP and UDP using proper network 
infrastructure controls, such as firewalls, UTM devices, or other security 
appliances. For more information on TCP/UDP ports used by Rockwell Automation
Products, see Rockwell Automation's Knowledgebase Article ID 898270 which is 
available at the following location: (link 
is external)

Minimize network exposure for all control system devices and/or systems, and 
help confirm that they are not accessible from the Internet.

Locate control system networks and devices behind firewalls, and use best 
practices when isolating them from the business network. The Common Plant-wide
Ethernet (CPwE) guide provides recommendations for deploying a plant-wide 
architecture: Industrial Firewalls within a CPwE Architecture

When remote access is required, use secure methods, such as Virtual Private 
Networks (VPNs), recognizing that VPNs may have vulnerabilities and should be
updated to the most current version available. Also recognize that VPN is only
as secure as the connected devices.

ICS-CERT reminds organizations to perform proper impact analysis and risk 
assessment prior to deploying defensive measures.

ICS-CERT also provides a section for control systems security recommended 
practices on the ICS-CERT web page. Several recommended practices are 
available for reading and download, including Improving Industrial Control 
Systems Cybersecurity with Defense-in-Depth Strategies.

Additional mitigation guidance and recommended practices are publicly 
available in the ICS-CERT Technical Information Paper, 
ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation 
Strategies, that is available for download from the ICS-CERT web site.

Organizations observing any suspected malicious activity should follow their 
established internal procedures and report their findings to ICS-CERT for 
tracking and correlation against other incidents.

No known public exploits specifically target this vulnerability. Not remotely
exploitable. High skill level is needed to exploit.



A remote, unauthenticated attacker could send a single, specially crafted 
Programmable Controller Communication Commands (PCCC) packet to the controller
that could potentially cause the controller to enter a DoS condition.

CVE-2017-7924 has been assigned to this vulnerability. A CVSS v3 base score of
7.5 has been assigned; the CVSS vector string is 


Mark Gondree of Sonoma State University, Francisco Tacliad and Thuy Nguyen of
the Naval Postgraduate School reported this vulnerability.


Critical Infrastructure Sector(s): Critical Manufacturing, Food and 
Agriculture, Transportation Systems, Water and Wastewater Systems

Countries/Areas Deployed: Worldwide

Company Headquarters Location: Milwaukee, Wisconsin

Contact Information

For any questions related to this report, please contact ICS-CERT at:

Email: (link sends e-mail)

Toll Free: 1-877-776-7585

International Callers: (208) 526-0900

For industrial control systems security information and incident reporting:

ICS-CERT continuously strives to improve its products and services. You can 
help by choosing one of the links below to provide feedback about this 

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